Previous studies have produced an antibody specific to prostatic acid phosphatase band 2a. This proposal includes an effort to produce monoclonal antibody to acid phosphatase band 4. The antibodies will be used for electron microscopic-immunocytochemical studies of these enzymes in prostatic as well as non-prostatic cells in order to learn the normal secretory mechanism of the prostatic epithelial cells, and look for alterations in prostatic cancer cells. (5)